python/src/pywy/platforms/commons/channels.py

#
#  Licensed to the Apache Software Foundation (ASF) under one or more
#  contributor license agreements.  See the NOTICE file distributed with
#  this work for additional information regarding copyright ownership.
#  The ASF licenses this file to You under the Apache License, Version 2.0
#  (the "License"); you may not use this file except in compliance with
#  the License.  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.
#

from typing import Callable
from pywy.core import (Channel, ChannelDescriptor)
from pywy.exception import PywyException


class CommonsCallableChannel(Channel):

    udf: Callable

    def __init__(self):
        Channel.__init__(self)

    def provide_callable(self) -> Callable:
        return self.udf

    def accept_callable(self, udf: Callable) -> 'CommonsCallableChannel':
        self.udf = udf
        return self

    @staticmethod
    def concatenate(function_a: Callable, function_b: Callable):
        if function_a is None:
            raise PywyException("the function_a can't be None")
        if function_b is None:
            return function_a

        def executable(iterable):
            return function_a(function_b(iterable))
        return executable


class CommonsFileChannel(Channel):

    path: str

    def __init__(self):
        Channel.__init__(self)

    def provide_path(self) -> str:
        return self.path

    def accept_path(self, path: str) -> 'PyIteratorChannel':
        self.path = path
        return self


COMMONS_CALLABLE_CHANNEL_DESCRIPTOR = ChannelDescriptor(type(CommonsCallableChannel()), False, False)
COMMONS_FILE_CHANNEL_DESCRIPTOR = ChannelDescriptor(type(CommonsFileChannel()), False, False)